Necrosis wrote:(Quake and HL are the same engine, except that HL is slightly improved)

Untrue...
At one time, circa 1996, Half-Life development began using the Quake engine, the (at the time) current state of the art. After a year of development, Valve looked at their project in dismay and knew that they had to do better. Their Quake engine, already heavily modified, was rebuilt from the ground up. Some Quake code does remain according to Gabe Newell, as well as some Quake 2 stuff, but the engine is soooo far removed from what they had going in 1997 that it would not be accurate to say that HL "uses the Quake engine". You could say that id Software pioneered the work for them, but they took it way beyond the scope of either Quake or Quake II.

Necrosis wrote:(Quake and HL are the same engine, except that HL is slightly improved)

Untrue...
At one time, circa 1996, Half-Life development began using the Quake engine, the (at the time) current state of the art. After a year of development, Valve looked at their project in dismay and knew that they had to do better. Their Quake engine, already heavily modified, was rebuilt from the ground up. Some Quake code does remain according to Gabe Newell, as well as some Quake 2 stuff, but the engine is soooo far removed from what they had going in 1997 that it would not be accurate to say that HL "uses the Quake engine". You could say that id Software pioneered the work for them, but they took it way beyond the scope of either Quake or Quake II.

"Yeah, whatever"

I know... I'll shut up now.
*goes back to the corner.

That is in definition of licensing incorrect.

HL is based very much off of the original Quake engine, and of course, like all licenses, modified and improved upon... while this is certainly evolutionary, it is still a common base. In the end, it has been quoted that there are in total roughly 100 lines or less of Quake II engine code which were essentially just patches for the Quake I engine.

The thing that distract people a lot is that the original Quake engine was released before the rush of 3d acceleration, so had a focus on performance to software rendering (which limited models and resolution) but did have the base for the accelerated setup (hence the release of GLQuake shortly after. Half-Life, on the other hand, was designed graphically with 3d acceleration in mind, which changes things dramatically, which is why people are so quick to rub off its Quake engine roots, which just isn't true. The Quake engine, at the time of its release was incredibly future-proof, however, the game content that came with it was less so.